Support undoing offline page deletion

components/undo/bookmark_undo_service.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/undo/bookmark_undo_service.h"
 
 #include "components/bookmarks/browser/bookmark_model.h"
 #include "components/bookmarks/browser/bookmark_node_data.h"
 #include "components/bookmarks/browser/bookmark_utils.h"
 #include "components/bookmarks/browser/scoped_group_bookmark_actions.h"
@@ skipping 384 matching lines @@
   for (size_t i = 0; i < ordered_bookmarks_.size(); ++i) {
     if (ordered_bookmarks_[i] == old_id)
       ordered_bookmarks_[i] = new_id;
   }
 }
 
 }  // namespace
 
 // BookmarkUndoService --------------------------------------------------------
 
-BookmarkUndoService::BookmarkUndoService() : scoped_observer_(this) {
+BookmarkUndoService::BookmarkUndoService()
+    : model_(NULL), scoped_observer_(this) {
 }
 
 BookmarkUndoService::~BookmarkUndoService() {
 }
 
 void BookmarkUndoService::Start(BookmarkModel* model) {
+  DCHECK(!model_);
+  model_ = model;
   scoped_observer_.Add(model);
 }
 
 void BookmarkUndoService::Shutdown() {
+  model_ = NULL;
   scoped_observer_.RemoveAll();
 }
 
 void BookmarkUndoService::BookmarkModelLoaded(BookmarkModel* model,
                                               bool ids_reassigned) {
   undo_manager_.RemoveAllOperations();
 }
 
 void BookmarkUndoService::BookmarkModelBeingDeleted(BookmarkModel* model) {
   undo_manager_.RemoveAllOperations();
@@ skipping 59 matching lines @@
   undo_manager()->EndGroupingActions();
 }
 
 void BookmarkUndoService::OnBookmarkRenumbered(int64 old_id, int64 new_id) {
   std::vector<UndoOperation*> all_operations =
       undo_manager()->GetAllUndoOperations();
   for (UndoOperation* op : all_operations) {
     static_cast<BookmarkUndoOperation*>(op)
         ->OnBookmarkRenumbered(old_id, new_id);
   }
+
+  if (model_)
+    model_->OnBookmarkRenumbered(old_id, new_id);
 }